End mills are manufactured in a variety of diameters, lengths, and materials. End mills are expensive and for example, a basic set of six end mills having three quarter inch shanks, of regular length and for example, four to six flutes with diameters ranging from three quarters inch to one and one half inches may cost over $100.00.
It is important for machine shops to have available apparatus for sharpening end mills as it is virtually impossible to hand sharpen end mills to have the proper primary and secondary reliefs and clearances. Improperly sharpened end mills greatly reduce the cutting efficiency and chip handling ability.